Letters of alphabets no from 1 to 26 are consecutively with 1 assigned to A…

Letters of alphabets no from 1 to 26 are consecutively with 1 assigned to A and 26 to Z. By 27th letter we mean A, 28th B. In general 26m+n, m and n negative integers is same as the letters numbered n.

Let P = 6, strange country military general sends this secret message according to the following codification scheme. In codifying a sentence, the 1st time a letter occurs it is replaced by the pth letter from it. 2nd time if occurred it is replaced by P2 letter from it. 3rd time it occurred, it is replaced by P3 letter from it. What is the code word for ABBATIAL